It's sink-or-swim time.

“Justice League” did little to disabuse audiences of the notion that the cinematic universe of which it is a part remains a dubious proposition, but the franchise isn’t underwater yet. That may change somewhat with “Aquaman,” a new trailer for which just surfaced at Comic-Con. Watch it below.

Jason Momoa plays the superhero of the title, heir to the underwater kingdom of Atlantis and reluctant mediator of a conflict between his subjects and the landlubbers above. “My father was a lighthouse keeper,” Momoa narrates as the trailer opens. “My mother was a queen. The light is a way of bringing people together.”

Per its synopsis, the film “reveals the origin story of half-human, half-Atlantean Arthur Curry and takes him on the journey of his lifetime — one that will not only force him to face who he really is, but to discover if he is worthy of who he was born to be…a king.”

Amber Heard, Patrick Wilson, Willem Dafoe, Yahya Abdul-Mateen II, Temuera Morrison, Dolph Lundgren, and Nicole Kidman all co-star. James Wan is directing the film, his first outside the “Insidious” and “The Conjuring” franchises in more than a decade. Warner Bros. will release “Aquaman” on December 21.

“Shades of Blue” is over, but Lopez’s “World of Dance” continues as a big hit for NBC. As she winds down three years of both her drama series and her Vegas residency, here’s what’s next for the superstar.